Myriophyllum.] XXXIV. HALORAGEA. 173 
Stamens 4or8. Stigmas and seeds 4 . : 3 : : . Ll. MYRIOPHYLLUM. 
Stamen, stigmaand seed1 . 3 : : : : . sip oy HIRE URIS. 
I. MYRIOPHYLLUM. WATER-MILFOIL. 
Aquatic plants, with finely pinnated, whorled leaves, and minute, 
sessile, moncecious flowers. Calyx with 4 short divisions. Petals 4 in 
the male flowers, very minute or none in the females, Stamens in the 
males 8, 6, or 4. Ovary and capsule of the females short, divided into 
4 cells, with 1 seed in each. 
A small genus, widely diffused over almost every part of the globe. In 
its finely-cut whorled leaves it bears at first sight much resemblance to 
Ceratophylium, but the lobes of the leaves are pinnate, not repeatedly 
forked as in the latter plant. 
Floral leaves or bracts not longer than the flowers 1. M. spicatum. 
Floral leaves longer than the “flowers, Nee pinnate like the 
stem-leaves ‘ : ? . 2. M. verticillatwm. 
1. M. spicatum, Linn. tag 395). Spiked M.—Rootstock perennial, 
creeping and rooting in the mud under water. Stems ascending to the 
surface, but usually wholly immersed, varying in length according to 
the depth of the water, and more or less branched. Leaves whorled, in 
fours or sometimes in threes or in fives, along the whole length of the 
stem; the numerous capillary segments entire, 3 to near 6 lines long. 
From the summit of the branches a slender spike, 2 to 3 inches long, 
protrudes from the water, bearing minute flowers arranged in little 
whorls, and surrounded by small bracts seldom as long as the flowers 
themselves. ‘The upper flowers are usually males, their oblong anthers, 
on very short filaments, protruding from the minute calyx and petals. 
The lower ones are female, very small, succeeded bysmall, nearly globular 
or slightly oblong capsules, each separating ultimately ‘into 4 I-seeded 
carpels. 
In watery ditches, and ponds, throughout Hurope and Russian Asia. 
Extending all over Britain. Fl. all summer. A slender variety, with 
the whorls of the spike often reduced to a single flower, and the lower 
ones having leaves at their base like the stem-leaves, has been considered 
a distinct species, under the name of M. alterniflorum, DC. 
2. M. verticillatum, Linn. (fig. 396). Whorled M.—In deep, clear 
waters, the foliage is precisely that of M,. spicatum, but the flowers are 
all immersed in the water, in the axils of the upper leaves. In shallow, 
muddy ditches, the segments of the leaves are often shorter and fewer, 
and the flowers form a spike protruding above the water as in M. spicatwm, 
but the bracts or floral leaves are longer than the flowers, and pinnate 
like the stem-leaves: this form constitutes the M. pectinatum of some 
authors, but cannot be distinguished with any precision, even as a 
variety. 
In watery ditches and ponds, with M. spicatum, over the greater part of 
its geographical range, and in many countries ascommon. In Britain it 
appears to be rather scarce, but perhaps frequently overlooked from its 
flowers not appearing above the water. FV. all summer. [M. pectinatum, 
DC., is a variety with very short floral leaves. ] 
